Recent improvements in performance of electronic apparatuses have led to an increase in the number of heat generating elements built into one electronic apparatus as well as an increase in energy amount input to each of the heat generating elements, resulting in an increase in an amount of the heat generated in the electronic apparatuses.
A conventional heat dissipation method using a cooling fan requires additional energy for driving the cooling fan and therefore is not preferable because power consumption of an electronic apparatus increases so as to acquire higher heat dissipation performance. Moreover, this method is not efficient since the heat generated due to energy loss is dissipated by energy input. Additionally, the cooling fan requires a comparatively large space and is not suitable for small electronic apparatuses. Moreover, in electronic apparatuses such as smartphones and tablet-type devices that include a sealed housing, a current of air by the cooling fan cannot be formed and exhausted to the outside.
A conventional heat dissipation method using a heat pipe can quickly transport heat. However, a heat sink or a radiator plate is required for dissipating the heat, which require a comparatively large space and are not suitable for small electronic apparatuses. In some examples, the heat may be released to a housing of an electronic apparatus instead of a heat sink. However, the housings in electronic apparatuses have been reduced in surface area due to reductions in size and thickness of the electronic apparatuses and cannot provide high heat dissipation performance. Moreover, life shortening of a lithium-ion battery is a problem for high-performance mobile apparatuses such as smartphones and the release of heat to the housing increases an environment temperature in use of the lithium-ion battery and may result in decrease in battery capacity with the passage of time.
In some examples, temperatures of the individual heat generating elements are measured, and an energy amount input to the heat generating element(s) is limited when the measured temperature value(s) exceeds a predetermined threshold value. This method is intended to reduce the amount of heat generated by the heat generating element(s) and thereby suppress a rise in the temperature of the heat generating element(s). However, since the function of the heat generating elements (e.g., CPU performance) is impaired each time the temperature of the heat generating elements rises, this method sacrifices the performance of the heat generating elements.